Inflammation, as the major mechanism of disease, underlies vascular system collapse in sepsis ("septic shock") and the development of atherosclerosis. Both disease processes converge prominently in the 60-85 year age group wherein sepsis-related mortality reaches 45%, as compared to a 30% mortality rate encompassing all age groups. Proinflammatory cytokines induce acute phase protein response (APPR). APPR is manifested by the expression of a biomarker, C-reactive protein (CRP), and by elevated levels of serum amyloid proteins, complement proteins, coagulation factors, and protease inhibitors-each contributing to cardiovascular inflammatory injury. CRP and other biomarkers related to the inflammatory process have been the focus of recent epidemiological and clinical studies. Annually, this process underlies 1 million heart attacks, 783,000 strokes, and an estimated 750,000 patients hospitalized with sepsis in the United States. How a high cholesterol Western diet and other microbial and metabolic inducers of inflammation link APPR to atherosclerosis and sepsis awaits elucidation. The central hypothesis of this proposal is that the key intracellular adapter of innate immunity, MyD88, links proinflammatory cues to APPR in sepsis and atherosclerosis. Furthermore, we hypothesize that in response to proinflammatory, oxidant, and metabolic stress, MyD88-mediated signaling induces nuclear import of stress-responsive transcription factors (SRTFs) that are responsible for the genetic reprogramming underlying APPR. To test these two hypotheses, we will use recently-engineered novel cell-penetrating proteins that target MyD88, an adapter protein positioned proximally to Toll-like/IL1/IL18 receptors. To delineate specificity of nuclear import machinery in APPR, we will design, produce, and test cell-penetrating inhibitors to target importin (karyopherin) alpha 1 that shuttles SRTFs to the nucleus. Using animal models that manifest APPR, we will assess the in vivo mechanism of action and therapeutic potential of these cell-penetrating inhibitors. Feasibility for the proposed study is underscored by the applicant's recent advances to suppress the MyD88-STAT1/STAT3- and importin (karyopherin) alpha-mediated signaling pathways using cell-penetrating proteins and peptides. These advances are evidenced by a custom-designed SRTFs nuclear import inhibitor that effectively corrected the aberrant genetic programs for inflammation, apoptosis, tissue injury, and atherosclerosis. Further advances include a recombinant cell penetrating form of SOCS3 that effectively attenuated some of these mechanisms. Results from the proposed investigation will help to harness the potential of cell-penetrating proteins and peptides for use in translational studies, and provide an understanding of the signaling intermediates, crosstalk, and intracellular checkpoints that control APPR. Thus, the proposed studies meet the urgent need for new anti-inflammatory drugs to suppress APPR and its attendant cardiovascular system injury in sepsis and atherosclerosis. PUBLIC HEALTH RELEVANCE: We propose to further develop an innovative form of intracellular protein/peptide therapy to extinguish inflammation and injury to blood vessels in vital organs. Specifically, we will study experimental models of blood poisoning (sepsis) and hardening of arteries (atherosclerosis). Annually, these inflammation-based diseases underlie 1 million heart attacks, 783,000 strokes, and an estimated 750,000 hospitalized sepsis patients in the United States.